Given the task definition and input, reply with output. In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D". 

[header] How to buy dry ice [title] Pick up dry ice at your local grocery or general merchandise store. [step] Stores that sell dry ice include safeway, walmart, and costco. [substeps] Plan to pick up dry ice as close to the time you will need it as possible. <sep> (A) What's more, dry ice is especially a benefit when it comes to early winter air pollution. Dry ice, also known as " warm ice, " includes the following: melted ice, freezer burned, and the equivalent elements. (B) You want to make sure that your feet are dry enough before purchasing dry ice. If the area you're new to will likely be dry, you may want to move to the beach to dry ice ahead of time. (C) Since it is constantly changing from solid to gas, it has a very short shelf-life. Every 24 hours , 5-10 pounds of dry ice turns from a solid to a gas. (D) Dry ice is overfrozen, and can accumulate in spots where you will not need your dry ice. You can also buy dry ice at your home improvement store or online.

C